Project Summary For a person with stroke symptoms, rapid hospital-based treatment with intravenous alteplase is critical for superior patient outcomes. To rapidly deliver intravenous alteplase, several counties implemented a bypass policy that requires paramedics to bypass the local emergency departments and directly route patients to stroke centers. However, scientific evidence that the policy results in effective, higher quality and equitable care to stroke patients is limited. Our proposed study will test policy's effect on intravenous alteplase use, 30- day mortality and short- and long-term functional independence.. If higher benefit is observed, the policy could be extended to non-policy counties. In our preliminary work (funded by AHRQ K08 HS17965), we used a before-after design of two counties to test the policy's effect on treatment. Although our work showed higher treatment in one of the counties the evaluation was limited to two urban counties and did not control for secular trends. The proposed study will address the above limitations using the following three aims. First, we will examine if the bypass policy leads to increase in countywide intravenous alteplase use, mortality and short-and long term functional independence. For this analysis, we will leverage on the natural experiment that happened in the US in which counties implemented the policy at different times during an eight-year period (2006-2013). We will identify 896 counties with the policy and match them 1792 counties without the bypass policy (total n =2688) and use a difference-in-differences approach to examine the effectiveness of the policy. Second, we will examine if county factors (e.g., variation in policy components, urban/suburban/rural counties) are associated with differential effects on outcomes. Third, we will use a multiple case study design, a qualitative approach to perform in-depth evaluation of 24 counties (72 provider interviews) using interviews, county surveys and document analysis of the county stroke protocols, to explain the policy effect and identify the enablers of the policy's effect. We will use an explanatory sequential design, a mixed-methods approach, to integrate the breath of the quantitative data in aims 1 and 2 with the qualitative data in aim 3 and use a joint display to present the findings. This study is significant because it will provide an accurate estimate of the policy effect on patient outcomes. The study also fits with AHRQ' mission on study of healthcare models using comparative effectiveness methods, quantitative evaluation using large databases, special emphasis on sub- population such as urban-rural differences and a qualitative examination with the goal of identifying best practices for the counties.